Gasfilled incandescent cathode discharge tube



Nov. 21, 1933. HQLST 1,935,846

GAS FILLED INCANDESCENT CATHODE DISCHARGE TUBE Filed April 5, 1928Patented Nov. 21 1933 um rsn P TENT oFF cE 5, {192a, serial No. 267,623;

and in thelietherlands April 11, 1927 13 cl ims. (01'.- 115 363) *This'int ent'iorirelates to anielectrical device, more'particularly' adaptedfor use in rectifying mitlng currents, incandescent age between theelectrodesim determined by $118 Voltage 5 betweem Hid incandescentcathode and 8 point lylhg "the-amide and by the tente -ln order to=-limlt-as much as' possible the loss of energy by thaulflfliarydischarge,

a may between the auxdiary e "and' -the anodey 'sald" resistance '30"serving to limit to a minknumtheeurrent flow ing' between the auxiliarycathode the anode. The invention aflordsmial advantages with dischargetubes oi the said klnd ior greatcurrent intensities, at with"suchadlscharge tubes,

85 due to the neutralization ot the anode drop, the

lessor energy inthe discharge is diminished: by an amount almost equalthe productfioi the anode-drop andthe-current-intensity." r

fllieddisoharge tubesior-illuminating-purposes are knownalreadyin-whichateachend-of thetube, an anode is amnged; sm-rounding anelectron emitting cathode. 1 In suchwase "the cathode is directlyconnected electrically to the surroundinganode, so that nodischarge-between these electrodew is produced. 1 The obiectot thisconstruction is-to permit the current to both directions with the sameease.

A w rm adeviee mama:

to" the invention has the feature that the electron emitting'auxiliarycathode is in: smated from thear'iode. Prefefablythe electron emittingcathode is an "lficande scible cathode; In an; exceptionally suitablerjnqdepf construction the cathode isarran'gedwithin'a hollow body, the

-56 anode bein gplacedbetoreancpeniend of this it may be even bodyiandlnsulated therefrom. It is clear that in thisease the hollow body forcesthe ions to remain inhtheneighborhood of the anode. To leaverthe hollowbody they must" pass the anode. By forming the hollow bodyotmetal andproviding itewith a pole wire, a potential differing from that ofLtheanode may be givento the body, in order toiurther direct the ions to theanode. Tha anode:may be perforated. in suitable manner; for instanceitmay be made of gauze, to enablethepositive ions produced by theauxiliary dischargeto enter easily into the main discharge I'heinvention will be more clearly understood by reierring: totheaccompanying drawing which represents, by way of example, a dischargetube include'd'in alcircuit-iarrangement for the rectifyingofalternating current.

.1 The discharge tube l comprises an incandescent cathode'2 and an anode3. An auxiliary'incandescent cathode 4 is arrangedbehind the anode '3in; the interior of the hollowbody 5 which forms one structure with-theanode 3 but is electrically insulated therefrom. The anodemay consist ofa; gauze or perforated wall which allows positive ions produced by theauxiliary discharge to enter intothemain-discharge path. The cathode2-is connected to one end otthe secondary 6 of a.transformerHthe-primary otwhich is not illustrated. The Lotherend of thesecondary winding is connectedto the-anode 3. The cathode 2 andtheauxili'ary cathode 4 arebroughtuptothe required temperatureby currentsupplied from transformerwindings 7 and- 8. The auxiliary cathode 4isconnected to an intermediate point of thesecondary 6. so that betweenthe electrodes 41nd 3 'thereis only a comparatively small potentialdiflerencei The hollow body 5 which is electrically insulated from theanode, may be brought to'athe required potential by means of aconnection 9. V v v Asthe'bodyfi isto'direct the positive ions from theauxiliarycathode 4 to the anode'3, its potential mustbe higher. thanthat ofrthe cathode 4. As a rule, itsufllces that the potential of thememher-babe but afew volts higher than the potentlal ofcathode 4,although under circumstances higher than the potential of the anode 3.

-"To obtain'the proper potential forthe body 5, the lead 9 may beconnected to a tap of the transformer winding 6 which lies between theleft ,hahd -terminal'o! the transformer and that point to which thecathode 4 is connected. Or a storagebaitt'ery maybe connected betweenthebody 0 5 and the auxiliary cathode 4. In both of these cases analternating potential is applied to the body 5.

If it isdesired to apply a directpotential to the body 5, the lead 9 isconnected through abattery to the middle point of the secondary wind ingof transformer 8.

In any case, it is preferable to limit the current.

flow between the body 5 and the cathode 4 by providing a resistance inthe, circuit branch leading to the body 5. The battery potential in theabove cases is preferably of the order of 8 to 10 volts.

WhatIclaim is:

1. An electric discharge device compris'ing a gasfilled envelope, ananode, and an incandescible cathode therein, means to neutralize theanode drop, said means comprising an auxiliary incandescible cathodedisposed in the vicinityot the anode, and insulated therefrom, saidauxiliary .cathode .having an electron emission of such magnitude to.produce an auxiliary discharge between said auxiliary cathode and saidanode to. furnish a suflicient number of positive ions to neutralize theanode drop. l

2. An electric discharge device comprising a gasfllled envelope, andanode, and an incan-r descible cathode .therein, means to neutralize theanode drop, said means comprising an auxiliary incandesciblecathode onthe far side of the. anode from the main cathode and having an electronemission of sufiicient magnitude to pro duce an auxiliary dischargebetween said auxiliary cathode and said anode to furnish a sunlcientnumber of positive ions to neutralize the anode drop.

1 3. An electric discharge device comprising a gasfilled envelope, ananode, and an incandesci: ble cathode therein, means to neutralize theanode drop, said means comprising an auxile .iary 'incandescible cathodespaced, from said anode at a distance shorter than that between the maincathode and the anode, and a screen on the far side of the auxiliarycathode from the anode, and having a lead wire sealed through the.envelope. Y

, 4. An electric discharge device comprising an.

envelope, an'incandescible cathode, an auxiliary cathode, a open-ended,hollow metal body surrounding the auxiliary cathode, a perforated anodedisposed in front of; the open'end of the hollow. body and insulatedtherefrom as well as from the other electrodes, and a lead wire fromsaid body sealed through said envelope, said electrodes being disposedin'said-envelope. g

5. In combination an electrical discharge.device, comprising a. sealedgasfllled-envelope, an

anode, an incandescible main cathode, and an auxiliary cathode therein,said auxiliary cathode being disposed at a shorter distance Irom..the

anode than the main cathode, and'a sourceof electric supply connected.to the electrodes Ior causing current flow between the main cathode.

I and theanode and between the auxiliary'cathode and the anode, thelast-mentioned current having a value sufflcient to produce ionssubstantially neutralizing the anode drop of the discharge between themain electrodes.

6. In combination, for rectifying alternating currents, an electricaldischarge device, comprising a gasfilled, sealed envelope, an anode, an-

incandescible main cathode, and an auxiliary cathode therein, saidauxiliary cathode being dis: posed at, a shorter distance from thevanode han the main ca e n de circuit comp i n main discharge;

a source of electric supply across the main cathode and the anode, andacross the anode and auxiliary cathode, and means for limiting thecurrent transmitted between, the anode and the auxiliary; cathode to, avalue at which the-number of positive ions is suiiicient to"substantially neutralize the anode drop of the discharge between themain electrodes.

7. In combination, an electric discharge device comprising ananode, anincandescible cathode, an auxiliary incandescible cathode inthevicinityoithe anode, a gasfilled envelope for the electrodes and acircuit comprising an electric supply source, and means by which currentis transferred between the main cathode and the anode and between theauxiliary cathode and the anode, the last-mentioned current having avalue sufllcient to provide for ions substantially neutralizing theanode drop of the discharge between the main electrodes.

'8'. In combination, anelectric discharge; device comprising a gasfilledenvelope, an anode, an incandescible cathode, and an auxiliaryincandescible cathode inthe vicinity ofthe anode dis, posed in-saidenvelope, and a, circuit comprising an electric supplysource and atransformer connected to said, supply source and providedwith secondarywindingby which currentjs transferred between the main cathode and theanode and between the auxiliary cathode and the anode, thelast-mentioned currenthaving a value suin cient' to provide for. ionssubstantially neutralizing the anode drop of the dischargebetween themain electrodes. I

9. In combination, an electrical discharge,dee

1 vice, for rectifying alternating currents comprising a-sealedgasfllled' envelope, a main cathode, and an auxiliary cathode in saidenvelope, said auxiliary cathode beingdisposedat a shorter distance fromthe, anode than the main cathode, and a; circuit, comprising an;electric supply source, means bywhich current is transferredbetweenthemaincathode and the anode, and a resistance in circuit with theauxiliary cathode and the anode for limitingthe .1current trans-' mittedbetween the anode andthe, auxiliary cathode to a ,valueat-whichasufilcientnumber, of positive ions are furnished to substantiallyneutralize the anode drop of the discharge between the main electrodes.Y

.10.. The om i at n oi, a e c r c di a e device compri ing agasfilled'enyelopafinanode, an incandescible cathode, and an auxiliaryincandescible cathode therein; said auxiliary cathode being disposed inthe vicinity of the anode, a

screen 'on the far side 01" the auxiliary cathode I I1. gasfllle'd'incandescible "cathode discharge tube adapted'to be used in, a devicefor rectifying alternating currents,comprising an env lo e, o'pen endedhollow body ofelectrically 'conduc r ve material therein, a maincathode, anincan iescible' electron eniittingauxiliary, cathode arrai dth g s i holler eh a d an ano 15o placed before the open end of saidbody and I insulated therefrom.

12. A gasfilled incandescible cathode discharge tube adapted to be usedin a device for rectifying alternating currents, comprising an envelope,an open ended hollow body of electrically conduc/ tive material therein,a main cathode, an electron emitting incandescible auxiliary cathodearranged within said hollow metal body, a lead for said body sealedthrough said envelope, the anode being placed before the open end ofthis body and insulated therefrom.

GILLES HOLST.

